Candy,
A suggestion would be to look through the individual websites posted on the Panhellenic site:
University of Southern California Panhellenic . See the photos, awards, philanthropies, social activities and scholarship standing.
The best sorority is the one that fits YOU. It is a mutual selection. Chapters at SC are very large, over 100 women. Last year the quota was 64 for a pledge class. With that number of new members each year a house can change drastically in one or two years.
Try to make your own decision after looking at the websites, meeting sorority women at orientation and visiting each chapter during the recruitment week. Try to go through with an open mind and find a chapter where you feel the strongest feeling of sisterhood.